- 15180 - Heating and Cooling Piping
- 15700 - Heating, Ventilating, Air Conditioning Equipment
- 15730 - Unitary Air Conditioning Equipment
- 15750 - Humidity Control Equipment
- 15800 - Air Distribution
- 15810 - Ducts
- 15820 - Duct Accessories
- 15840 - Air Terminal Units
- 15850 - Air Outlets and Inlets
- 15860 - Air Cleaning Devices
- 15915 - Electric and Electronic Control
- 15935 - Building Systems Controls
- 23 09 33 - Electric and Electronic Control System for HVAC
- 23 20 00 - HVAC PIPING AND PUMPS
- 23 21 13 - Hydronic Piping
- 23 21 23 - Hydronic Pumps
- 23 22 13 - Steam and Condensate Heating Piping
- 23 22 23 - Steam Condensate Pumps
- 23 23 00 - Refrigerant Piping
- 23 25 00 - HVAC Water Treatment
- 23 30 00 - HVAC AIR DISTRIBUTION
- 23 31 00 - HVAC Ducts and Casings
- 23 31 13 - Metal Ducts
- 23 31 16 - Nonmetal Ducts
- 23 33 00 - Air Duct Accessories
- 23 33 46 - Flexible Ducts
- 23 35 13 - Sawdust Collection Systems
- 23 36 00 - Air Terminal Units
- 23 36 13 - Constant-Air-Volume Units
- 23 36 16 - Variable-Air-Volume Units
- 23 37 00 - Air Outlets and Inlets
- 23 37 13 - Diffusers, Registers, and Grilles
- 23 37 23 - HVAC Gravity Ventilators
- 23 40 00 - HVAC AIR CLEANING DEVICES
- 23 41 00 - Particulate Air Filtration
- 23 41 33 - High-Efficiency Particulate Filtration
- 23 41 43 - Ultra-Low Penetration Filtration
- 23 43 00 - Electronic Air Cleaners
- 23 50 00 - CENTRAL HEATING EQUIPMENT
- 23 60 00 - CENTRAL COOLING EQUIPMENT
- 23 70 00 - CENTRAL HVAC EQUIPMENT
- 23 80 00 - DECENTRALIZED HVAC EQUIPMENT
- 23 81 00 - Decentralized Unitary HVAC Equipment
- 23 81 13 - Packaged Terminal Air-Conditioners
- 23 81 16 - Room Air-Conditioners
- 23 81 26 - Split-System Air-Conditioners
- 23 84 00 - Humidity Control Equipment
- 23 84 13 - Humidifiers
- 23 84 16 - Dehumidifiers
- 23 84 19 - Indoor Pool and Ice-Rink Dehumidification Units
- 25 00 00 - INTEGRATED AUTOMATION
- 44 11 16 - Industrial Dust Collectors